Acttually the issue with outbound federation not properly working is from before they upgraded to 0.19.0-rc4, but 0.19.X made it even worse, because it breaks various clients, e. g. Jerboa, due to some breaking API changes it introduces.
Honestly, this unannounced upgrade to 0.19.X is quite a kick in the butt.
Also broke the inbox on desktop, was showing empty for me even though it shows the notifications. I had to manually go to the thread to see this message (lucky I keep tabs open).
I agree that this unannounced upgrade is quite the shock to the system and also lemmy 0.19 hasn't even officially dropped yet so it seems kind of strange to update to it now.